Telephone system



Sept. 28 1926.- 1501;053-

. 5 B. WILLIAMS I TELEPHONE SYSTEM Original Filed e 1924 8 Sheets-Sheet2w Sept. 28, 1926. 1,601,053

s. B. WILLIAMS TELEPHONE SYSTEM Origml Filed June 1924 a Sheets-Sheet 5T;

.lm e/lfarx I Jdmae/bl llW/famz WW, my

S. B. WILLIAMS TELEPHONE SYSTEM Sept. 28 l926.- 1,601,053

- OriginaL June 1924 8 Sheets-Sheet 4 by WWW Sept. 28, 1926. 1,601,053

S. B. WILLIAMS TELEPHONE SYSTEM Original Filed June 27, 1924 aSheets-Sheet 6 &

Se t. 28, 1926. 1,601,053

- B. WILLIAMS TELEPHONE SYSTEM Original Filed June 27. 1924 8 sheets-4m7 Sept. 28,1926. 1,601,053

' 5 B. WILLIAMS TELEPHONE SYSTEM 1 original Filed June 27. 1924 v 5h t-$he t 8 lm emort Ja/m/e/ A [MW/arm Any . Patented Sept. 28, 1925.

neat-5i unirsn stares earner os rich.

SAMUEL 13. WILLIAMS, 0F BROOKLYN, NEW YORK, ASSIGITGR TO .UE STERNELECTRIC COMPANY, INCURPGRATED, OF NEX -1' YORK, Y., A COREORATION OFNEW YORK.

TELEPHONE sYs'rEM.

Application filed June 27, 1924, Serial No. 722,631. Renewed April 5,1926.

This invention relates to telephone systems, and moreespecially tosystems of this 0 iaracter which utilize automatic switching equipmentfor the establishment of conversationalconnections. 2

in systems employing common controlling mechanisms located at thecentral office and serving to govern'and control the selective operationof the automatic switches, it frequently happens that one of thesemechanisms encounters trouble while in the eXer- It is, therefore, theobject of. this inven- 7 tion to release a disabled controllingmechanism without defeating the connection which is undergoing extensionand to thereupon take in use either the same or another mechanism foranother trial.

' controlling a selective switch together with means for disconnectingthe marker from the sender if such marker fails to function, withoutdisturbing the connection undergoing extension, and to connect saidsender to one of said markers for a retrial.

A further feature relates to means for preventing the sender fromreconnecting to any marker which has encountered trouble and beenreleased. 2

Referring tothe drawing, Figs. 1 to 8, inclusive. when taken in theorder illustrated in 9, disclose a portion of a telephone exchangesystem embodying the features of this invention.

Fig. 1 shows schematically a subsc-ribers line, a line" switch, a trunkoutgoing there-- from, a sender selectorrswit'ch, and a portion of asubscribers register; sender. Fig. 2 shows a district selector switch inwhich terminate the trunks leading from the Fig. 4 shows a multi-contactrelay connecting device for associating the senders with the markers. 1'

F igs. 5, 6 and 7 illustrate one of a number of controlling markers, thefunction of which is to determine the selective and testing operation ofthe selective switches such as the one shown in Fig. 2. l

8 shows a frame connectorfor conne'cting the markers to the frames ofthe switches shown in Fig. 2 and also'a'trunk connector for associatingthe marker with the different groups of trunks outgoing from theselector switches.

The system disclosed herein is an improvement upon the type of systemillustrated and described inthe patent of S. B. lVilliams, 1,517,331,Dec-2, 1924:, to Whichreference is hereby made for an understanding ofthe various operations which may hereinafter be referred to but notspecifically described General descflptz'mt 0f the apparatus andopcmzfion.

The callingsubscribers lines, such as'the line 100, terminate-invertical rows of con tacts in coordinate line switches 101. Theseswitches 'have'access to groups of trunks, such as the trunk 102, whichextend and appear in vertical rows of contacts in district selectorswitches. The trunk 102, for exanr ple, appears in the vertical row 201of the selector-200. Another trunk 21 1- sin'iilarly occurs in thevertical row of contacts 202 and still other trunks maybe provided.

Thedistrict selector switch 200 contains. a number of vertical rows ofcontacts 203, 20 1, etc., in which appear numerical groups of trunksoutgoing to succeeding switches.

The switches'101,108.200, etc., are of the coordinate type comprising aplurality of intermediate or horizontal links, "together with verticalandhorizontal selecting'and operating bars and individual magnets foroperating these bars. The district selector 200, for instance, has anumber of links 205, 206', 207 208, etc., with individual operating bars215,216. 217 and 218 and the respective horizontal operatingmagnets 219,220, 221 and 222. Furthermore, the switch has. vertical selecting bars209, 225, 213,, etc., to; gether" with corresponding operating magnets210, 211 and 212.

l tit? r The trunks 102 leading from .the line switches to the districtselector also appeal. l

in the rider selector switches 108. These selector switches have accessto a number of recording senders, one of which is partially shown inFig". land in Fig. 1.

The register senders have an appearance in the sender connecting devices100, each diiterent sender being represented by a ditt'erentniul'ti-contactrelay -103, .04, etc. The device s'lOO is-also providedwith anun'iber of relays Z10, $12, etc., each of which represents' adiil'erent one of the controlling marlters. By operating the proper pairof these relays, any sender may be connected to any marker.

The marker includes a number of registers 500, 501 and which receive theotlice portion of the entire designation, made up of three separatedigits, from the register sender. Furthermore, a translating de vice 500.is comprised of a number of sets of multi-contactrelays 510, 511, 512,etc, and 518, 514, 515, etc. and relays 507, 508 and 509. The registerscooperate with this translating device in such a manner as to determinethe selection of the group relays 612, 613, 614:, 615, etc. These grouprelays determine the particular groups of trunks outgoing from theselector switches, which must he invo red to route tie call in thedirection corresponding to the designation transn'iitted to the sender.

The marker also determines the selection and operation of the proper oneof the trains connectors 800 in order to associate itself with then'roup of district trainee 200 containing the frame in which appears thetrunl: over which the connection has been extended tromthe calling line.This frame connector 800 includes a number of relays S02 and 803. eachindividual to a different one of a plurality of markers. it alsoincludes a number of multi-contact relays st and 805, each individual toa particular district trams 200 in the group. Relay 805. for instance,is individual to the particular trams 200 shown in the drawing.

The trunk connector 801 comprises a numher of relays 810 and 811 eachindivid ual to a ditferentn'iarker. he connector 801. in additionincludes a number ot' relays 812 and 813 each of which is individual toa dii'l'erent group of trunks outgoing from the district frames 200. Thetrunks ot each group may be multiplied to appear in as manyselectorswitc-hes as may be desired.

The marker is'equipped with a testing de vice consisting ott-a number ofsets oi testinc relays 2'00. These relays serve to test the horizontallinks and the correspondino outgoing trunks of any group. i i?Anothe1*fu-nction ot' the marker is to terinine trointhe. ollice coderegistration which it receives from a sender. the nature or class ottheconnection-that is to beer;- tended;

This" it does through'the medium.

of a translator 506 and may cause the operation of one of a number ofclass relays 528. These class relays, or the translator itself, maydirectly cause the closure of circuits extending' back into the sendertor the operation of the proper class relays therein, thusgiving thesender the necessary intorniation to enable it to prepare to exercisethe necessary control over the connection involved.

T he line switch 101 and selector switches 200 and 108 may he of thegeneral construction and operation as the one shown and described in thepatent of C. L. Goodrum and J. N. Reynolds, No. 1,515,735, Nov. 16,.1924.

Detailed description of tile establishment of a connection.

It will now beassumed for the purpose describing the invention, that thesubscriher of line wishes to obtain a connection extendingthrough thedistrict selector s itch 200. The calling subscriber in initiating thecall, causes the operation of line switch 101 to extend his line over anidle trunl; 102 to the district switch 200. The "initiation of the callalso causes the operation of sender selector switch 108' to associatethetrunk 102 with the idle register senocr shown in the drawing. Duringthe operation of the sender selector-switch 108, aClltliltls'('OlIlPlQtQt tor operating the relay 10 -l. The relay 10-1completes a hold ing circuit for the slow-release relay 100 which hasbeen previously operated. This holding circuit leads through the lowercontact 0t relay 10st and the contact of relay 106. As soon as thesender selector switch 108 and the line switch 101 have operated, thesuhv'icrih rs line included in series with the impulse relay 300 in thesender. The circuit o this purpose may be traced from batter through'theright winding of relay 300, outer right contact ot relay 310, thencethrough the sender selector switch 108, over the ring of the trunk 102,through the line switch 101, over the loop of the line 100, andreturning through the'line switch 101 and the sender selector 108, innerright. contact of relay 310, to ground through the right winding" thebalancing coil S03. lay 300 operates and closes the circuit for theslow-release holding relay 301. Relay 301 completesoperating circuitstorthe re lays 302 and 316. These relays lock in circalls from battery,through theirwindines. thence through the inner right contact et relay3091,1038] contact-0t the relay 310, to ground at the inner left contactof relay (.32. Relay 30?. applies ground potential through K391111161lettcontact, left hacltcontact ot' relay 310, to the conductor-3l lwhichssrres to hold the sender selector switch 108 and the relay 10% inoperated condition,-

Recording thedesz'gncton in the sendcax- Thesubscriber now manipulateshis dial (not shown) to transmit a number of impulse. representing theWanted designation. The impulse relay 300 responds to these impulses andcooperates with relays 305, 306, 30?, 303 and 309 and with a set ofcounting relays diagrammatically illustrated by the rectangle 304, tocause the setting 03": a corresponding number of registers illustrateddiagrammatically by the rectangle 109. The general manner in which thetoregoi o; op-

erations may be accomplished. is dewibed and illustrated in the patentabove mentioned to S. B. \Villiams, No. 1,517,331, Dec. 2, 1924.

Association of the sender with an idle markevt+As soon as the firstthree of registers 109 have been operated, a circuit is closed extendingover conductor 318, through the Winding of relay 313, to battery. Relay313 operates and causes the operation of relay401 to initiate theactuation of the connector 400. The circuit for this purpose may betraced from battery. through the lower contact of relay 402, leftwinding; of relay 401, conductor 413, contact of relay 311, outer rightback contact of relay i, left contact of relay 313, conductor. 320,conductor 321, to ground at the contact of relay 316. Relay 401-operatesand closes a holding circuit from battery, through the Winding ofrelay402, right contact and Winding of relay 401, to ground over thecircuit above traced. Relay 401 holds and relay 402 operates in thislatter circuit. Relay 402 in operating, prevents the operationsubsequently of another relay similar to the relay 401., With the relay401 operated, niulti-contact relay 403 is energized in a circuit from.battery, through its Winding, left contactof relay 401', inner contactof relay 405, to gIO11I1Cl-;%1ti1e inner lower contact Fm Stirs v ofrelay 402. Relay 403 locks through its inner contact to ground at theupper con tact of relay 402. Relay-402 completes a start circuit toselect the first idle' one of the markers. Assuming that the markerappearing in the multi-contact'relay 412 is busy, and that the nextmarker illustrated is idle, this start circuit leads from ground,through the inner lower contact of relay 402, lower contactot relay 405,left front contact of relay 406, left back contact of relay 407,.leftback contact of relay 408, left winding of relay409, to battery at theouter contact of ,relay411. Relay 409 operates lay 409, conductori414,to ground at the inner lower contact of relay 402. Relay 409 locksuandrelay-411 operates .in this circuit.

Relay .411 causes the operation of relay. 408

inan;1obvi0us. circuit to identify the assoas above traced. Relay 600looks throt.

contact of relay the connector 400 over conductors 416, 41

ciate-d marker as busy. Moreover, relay 411 causes the operation of theinulticontact relay 410 in a circuit from battery, through the Windingof the latter relay, middle right contact of relay 409, to ground at theinner contact of relay 411.. With the relay 403 and 410 operated, theregister sender is connected through the connecting device 400 to themarker shown in 5, 6 and 7.

' As soon as, the connector 400 operates, the relay 600 in the marker isenergized, in a circuit from battery, through the winding of said relay.conductor 618, through the connector 400, to ground over conductor 413511 its inner right contact, outer ri ht back contact of relay 607, outeright 'contactot re lay 606, to ground at the inner left back It Will beassumed that the connection be ing extended is one involvinga local lineas a called line. Accordingly, the operation of relay 600 upon theseizure ot the marker, causes theoperation of the relay 711. The

circuit for this purpose leads from battery,

through the Winding of relay .711, inner right back contact or" relay710, conductor 622, inner right back contact of relay 606, to ground atthe inner left contact of relay 600. p

The record established on the registers 109 of tie sender is nowtransferred to the corresponding registers 500, 501 and 5020i themarker. The registers 500, 501, and 502 are made up of the relays 516 to527, inch".- sive, eachrcgister comprising four of these relays.Thesender registers 109gare1nadc up of corresponding relays which areoperated in different combinations in response to the subscribers dial.

lit will be assumed that the designation is such-that the third relaythe egistor of the sender, the first a d second relays of the secondregister, and the second relay of the third register of sender, areoperated. Accordingly, the corresponding relays 518, 520, 521 and 525 ofthe marker registers 500, 501 and 502 are energized. The circuit toroperating these, re lays extends from -round, through the inner leftcontact or relay 600, inne'rright back contact ot relay 606, outer ightcontact of relay 608, left contact of relay 604, conductor 619, thencethrough the connector 400, conductor 111, thence through the frontcontacts of the opearted register lays 109 in the sender and returningthrough i 413 and 419, through the windings of relays 518, 520, 521and525, respectively, to but tery. The remaining re gn-1 r relays oftheregisters 500, 501 and 502 are also temperarily energized by means of acircuit which may be traced from grounded conductor 619. thence overconductor 530, through t no -nor= I nal contact of relay 504, right backcontact of relay 503, conductor 415, through the connector 100, andthence through the back contacts of the register relays 109 which havefailed to operate and returning through the connector 400 over the corrspending conductors to the windings of relays 516, 517, 519, 522, 523,52 1, and 527, to battery. hen all the marker register relays hayoperated, a circuit is closed for operating re lay 503, which may betraced from batt U through the winding thereof, thence in series throughthe con'acts of the operated re ter relays to ground over conductor 550as previously traced. Relay S locks through its inner right frontcontact and the normal contact of relay 50% to the grounded conductor530. Relay503 at its right back cont opens'the o 'ierating circuits ofthe marker register relays which do not correspond to the operatedrelays in the sender, per-mitt these relays to release. The relay 503 acloses an obvious circuit for relay 501, wh operates and locks throughits own conta to the grounded conductor 53/. Relay 50%;- in turn opensthe holding circuit of re 503, permitting this latter relay to role;

F or an understanding of the manner in which the marker register relays(17G operated and released as above described, reference is made to theapplication of O. From, Serial No. 690,707,iiled Febrraiy 1924:.

Operation of the translator and selection of the proper trunk g'r0up.Thereg. 500, 501 and 502 having been set, the tra lator 506 is now operatedto prepare a cir cuit for selecting one of the group relays shown in theupper part of Fig. 6 to identify the proper group of trunks to beemployed in entendiug the connection through the district elector switch200. lVith the relay 518 of the register 500 operated, a circuit isclosed for operating the relay 50?, traceable from battery, through thewind- 111g of the latter relay, inner lower back contact of relay 519,inner lower front contact of relay 518, inner lower ack contacts ofrelays 517 and 516, conductor 532, left contact of relay 50st, to thegrounded conductor 530. Since the register relay 525 is operated, acircuit is closed for operating niultieontact relay 515 as follows:battery, through the winding of relay 515, inner lower trout contact ofrelay 525, inner lower back contact of relay 52a, to ground overconductor 82. Since the rela s 520 and 521 of register 501 are operated,a circuit is completed 101' operating the niulti-contact relay 512 andmay be traced from battery, through the Winding of the latter relay,through the distributing fame 533, contacts of relay 515, lower frontcontacts of relays 521 and 520, lower back contact of relay 523, to thegrounded conductor 532. The group relay 612 is now operated in a'circuitfrom battery, through the winding of this relay, distributing frame 620,conductor 621, tl rough the distributing frame 5341, contact of relay512, lower contact of relay 507, conductor 535, to ground at the outerleft contact of relay 60S, Relay 612 represents the group of trunksappearing in the veitical row 20% of the distri *t selector switch 200.

Operation of the district f'rrmte connec- Z 07r1 kt the time relay 50%operates, it closes an energizing circuit for relay 801' of the frameconnector 800. This circuit may be traced from battery, through theouter right contact of relay 60st, conductor 623, winding of relay 607conductor 819, outer right contact of relay 50-1, conductor 540, throughthe connector 100, conductor 110, right back contact of relay 322,conductor 523, thence oi'er conductor 111, through connector 100, toground over conductor 619 as previously raced. lielay S07 completes acircuit for 'elay 806 from battery, through the right ding of the latterrelay, front contact of y 807, back contact of relay 820, assumthisrelay to be deenergized, upper conrelay 809, to ground at the backconslow-release relay 808. When relay S06 is operated, it operatesslow-release relay 808 in a circuit from battery, through the winding ofrelay 808, lower back contact of relay 809, right contact of relay 806,conductor S21, outer left contact of relay 611, middle right contactofrelay 607, outer right contact of relay 608, conductor 622, inner rightback contact of relay 606, to ground at the inner left contact of relay600. The relay 808 operates and opens the operating circuit of relay806. Relay 806 being slightly slow to release, however, remainsenergized until relay 808 has fully operated. The holding circuit forrelay 806 is then closed from battery, through the left contact of relay806, left back contact of relay S23, winding of relay 809, to ground atthe front contact of relay 808. Relay 809' operates and opens thecircuit of relay 808. Relay 808 releases and operates the multi contactrelay 802. The circuit for this purpose leads from battery, through thewind ing of relay 802, outer left contact of relay 806, upper frontcontact of relay 809, to ground at the back contact of relay S. Relay809 being operated, prevents the operation of another of the relays 806and 823, thereby avoiding interference by other markers. After relay S08releases, relays 806 and 809 remain operated in acircuit which leadsthrough the lower front contact of relay 809. right contact of relay806, to the grounded conductor 821.

The vertical operating magnet 210 0011- trollingthe row of contacts 201in the switch 200. in which appears trunk 102, is now operated. Thecircuit may be traced frombatl L 'ict t of tery, through the winding ofsaid magnet, conductor .227, left back contact of relay 107, through theswitch 108, conductor 112, con nector 400, conductor 421, normal contactof relay 603, inner left back contact of relay 610, conductor 627through contacts of the frame. connector 800, to the grounded conductor821. The magnet 210 rotates the vertical bar 209 and prepares allcontacts in the row 201. Magnet 210 extends the grounded conductor 227through its inner lower contact, over conductor 228, through the windingof the multi-contact relay 805, to battery. Relay 805, which isindividual to the switch 200, operates and results in the connection ofthe conductors from the markers through to the frame of the, selectorswitch 200.

With the frame connector 800 operated, relay 608m the marker isenergized in a circuit from battery, through the winding of said relay,outer left back contact of relay 61.0, conductor 680, through theconnector 800, to the grounded conductor 821., Relay 603 at its normalcontact opens the circuit of magnet 210,but before this occurs saidrelay closes a substitute holding circuit for said magnet and also forrelay 805. The holding circuits be traced from battery, through thewinding and contact of magnet 210, conductor 228, and in parallel frombattery, through the winding and contact of relay 805, contact of relay802, conductor 824. make contact of relay 603, inner left back contact.of relay 610, to ground over conductor 627 as previously traced.

i The vertical magnet 210 operates the horizontal magnet 226 whichrotates the associated bar and prepares the special horizon tal link224. The relay 107 in the trunk 102 is now operated in a circuit frombattery, through its winding, conductor 113, through contacts of thelink 224, conductor 229, tlnroughthe connector 800, conductor 826,conductor 825, left contact of relay 603, to round at the left backcontact of relay 608. Relay 107 operates and at its left back contactopens the original energizing circuit of magnet 210. 7

Operation of the distinct trim-k o0nne0t0r.- Duringthe foregoingoperations, the district trunk connector 801 is also being operated forhe purpose of connecting the test relays 7 00 with the proper group oftrunks outgoing from the district selector 200. For starting the trunkconnector 801-in operation, the relay 815 is energized in a circuit frombait-cry. through the winding of said relay, duct-or 827 through thedistributing '1' me 620, outer left contact of group relay 612,conductor 628, middle left contact of relay 806, to ground at the backcontact of relay 808. Relay 815 operates the relay 814 in a circuit frombattery, through the left winding of relay 814, front contact of relay815, back contact of relay 828, upper back contact of relay 817, toground at the back contact of slow-release relay 816. Relay 814 whenoperated, causes the operation of relay 816 in a circuit from battery,through the .winding of the latter relay, lower back concircuit ofrelay816, which subsequently releases. After relay 816 releases, the relays814 and: 817 are held energized in a circuit is: lingthrough thelowerfrontcontact of reiay .817, left contact of relay 814, to thegrounded conductor 821. The multi-contact relay 810'is now operated in acircuit from battery, through its winding, outer right contact of relay814, upper front contact of relay 817, to ground at the back contact ofrelay 816. I The inulti-contact relay 812,

which is individual to the group of trunks appearing in the vertical row204 of the distr t selector 200, is operated in a circuit from battery,through its winding, conductoi 880, contact ofrelay 612, conductor 681,middle right contact of relay 814, to ground at the back contact ofrelay 816.

Testing Zia/cs audit-miles at the district selector swch.The I marker isnow pre pared to proceed witha test of the selected group of trunksoutgoing from the district selector 200 and also the correspondinghorizontal links. The rightwindings of the double wound test relays 701,702, 703, etc., serve to test the trunks 280, 281, 282, etc., in order.The left windings of these relays serve to test the correspondinghorizontal links 205, 206, 207, etc. The test circuit for the trunk 230may be traced from battery, through the right winding of relay 701, nextto the inner back contact of relay 708, right backcontact' of relay 706,conductor 714, through the trunk connector 801, conductor 831, to thesleeve conductor of the trunk 230. 'lhe'test circuit for thecorresponding link 205 may be traced from battery, through the leftwinding ofrelay 701, inner back contact of relay 708, conductor 715,through the frame connector 800, conductor286, tothe test connector ofthe link 205. In a similar manner the test circuits for the remainingtrunks of thegroup and of the correspond ing links may be traced throughthe windings of the test relays 800.

It will be assumed that the trunk 232 is the first trunk in the groupwhich is idle lil simultaneously with the idle condition of itsassociated llIl 207. Since each of the preceding trunks or each of thecorresponding preceding horizontal links is busy, or both trunk and linkare busy in each instance, the corresponding test relays 701, 702, etc.,are operated either. by the energization of one or of both windings.Since, however, the trunk L32 and its associated link 207 are both idle,the test relay 708 remains deenergized. The operated relays 701 and 702lock in circuits through their right windings and contacts, conductor717, inner right contact of relay 608, to the grounded conductor 622.

At the instant the testing operation commneces, a circuit is completedfor operating the vertical magnet 212 of the district selector 200. Thismagnet requires an appreciable interval in which to become fullyoperated and consequently serves to measure the time in which the relays800 are re quired to test the links and trunks and to assume theiroperated and non-operated c011- .ditions accordingly. The circuit formagnet 212 may be traced from battery, through the winding thereof,conductor 237, through the connector 800, conductor 832, contact ofrelay 612, conductor 629, through the trunk connector 801 to thegrounded conductor 821. lVhen magnet 212 is operated, it causes theenergization of relay 60 1 in a circuit from battery, through thewinding of relay 60%, normal contact of said relay, conductor 682,through the frame connector 800, conductor 238, to ground at the contactof magnet 212. The relay 604 locks through its inner right contact andthe inner left contact of relay 608 to the grounded conductor 622.

The relays 708 and 709 are now operated in circuits from battery,through their windings, thence over conductor 718, inner-right contactof relay 604, to ground over conductor 717 as above traced. Relays 708and 709 disconnect the test relays 700 to prevent their subsequentoperation. The relay 728 relating to the idle trunk 232 and link 207 isnow operated in circuit from battery, through the winding of relay 712,Winding of relay 728, left back contact of test relay 703, left frontcontacts of preceding energized test relays 702, 701, etc., conductor721. through the trunk connector 801. conductor 83 1, normal contacts ofrelay 605, contact of relay 607, thence to ground over conductor 718 aspreviously traced. Relay 712 also operated in this circuit.

Relay 712operates the relay 314 in the sender in a circuit from battery,through the winding of relay 314-, conductor 324, connector 400,conductor 420, conductor 636. inn-er right contact of relay 711, toground at the contact of relay 712. Relay 314'locks through its leftcontact to the grounded conductor 320. Relay'31 l at its outer rightback contact opens the original operating circuit of the relay 600.Relay 600, however, remains energized in the locking circuit previouslytraced,

The horizontal magnet 221 is next operated by means of a circuit frombattery, through the right winding of said magnet,

conductor 239, connector 800, conductor 8.3:), middle left contact ofrelay 728, to ground over conductor 717. Another circuit for magnet 221may be traced from battery, through both windings thereof, thence overconductor 234, through the connector 800, conductor 836, next to theouter front contact of relay 708, inner left contact of relay 728, tothe grounded conductor 717. The closure of this latter circuit alsoresults in placing a ground potential upon the test conductor of thehorizontal link 207. Magnet 221rotates the bar 217and effects connectionfrom the trunk 102 through the link 207 to the selected idle trunk 2232.

Returning to the point where relay 60loperates, it may be noted thatthis relay causes the release of the translator and marker registerrelays. Relay 604 at its left contact removed ground potential. fromconductor 619, causing the release of relay 50-1 and consequently therelease of relays 507, 512 and Relay 604 at its back contact opens thecircuit of relay 807. When the translator releases, the group relay 612is deenergized.

Release of the district frame (and firm/a connectors and 0f thewmflcen-The marker has completed its function in operating switch 200and should now be released in order that it may be taken into use inconnection with other calls. At the time the district selector switch200 operates to extend the trunk 102 through to the trunk 282,. acircuit is closed for operating the release relay 607. This circuit maybe traced from battery, through the winding of said relay, conductor635, right front contact of relay 728, conductor 730, conductor 7 3through the trunk connector 801, conductor 840, thence through thedistrict selector switch 200, sleeve conductor 115 of the trunk 102, toground at the contact of slow-release relay 106. Relay 607 locks throughits inner right contact; inner right contact of the relay 608, to thegrounded conductor 622.

It may be noted at this time that the horizontal operating magnet 221 isalso locked in a circuit from battery, through both its windings. thencethrough contacts of the switch 200, to the grounded sleeve conductor115, Therefore, this magnet will remain operated after the marker. whichfurnishes the operating circuit therefor. becomes released.

Relay 607 opens the holding circuit of relay 600 and this latter relaybecomes re leased. Relay 600 removes ground potential vertical magnets210 and 212 are from conductor 717, causing the release or" all operatedtestrelays. Relay 607 in op erating, removes ground potential fromconductor 821 causing the release of the frame connector 800, trunkconnector 801 and all operated'relays associated therewith. The

also released and the connection through the switch 200 is now held bythe continued operation of the horizontal magnet 221. Relays 603 and 604are also deenergized.

At the time the relay 314 is operated in the sender, the originalholding circuit of the relay L01 associated with the connector 400 isreleased. The relay 401, however, r mains operated in a circuit whichmay be traced over conductor are, conductor 116, thence through theconnector 400, conductor contact of relay 606, to ground at the innerleft contact of relay 602. When relay 607 subsequently operates as justexplained, the holding circuit of relaysl02 and 401 is also opened.These relays release, in turn causing the release of the connector 400and all energized relays associated therewith. Thus the marker has beencompletely released and disassociated from the selector switch 200 andfrom the sender.

Release 0; the sen(Ze'/*.From this point on, the connection may proceedin any suitable manner according to the class of the call concerned.Afterthe sender has completed its function, a circuit may be com--pleted for the release relay 310. Relay 81C opens the holdingcircuit ofthe impulse relay 800 which releases the slow relay 301. Relay30l inturn releases the holding relays 302 and 316. These relays move groundpotential from the holding conductors to permit the release of thevarious energized relays in the sender.

The sender in releasing, also causes the release of the sender selectorswitch 108 above mentioned patent of S. B. lh illiams,

1,517,331, Dec. 2, 1924.

The marker encounters tr0ubZe.-If at any time following the seizure ofthe marker for the purpose of controlling the extension of a connectionthe marker encounters trouble, as for instance the failure of a relay tooperate or for any other reason, the marker will cease its no *malprogress with the re sult that the selector switch cannot be operated.To prevent the connection which has been successfully extended to apartial completion from failing on account of such an occurrence, it isdesirable to discharge the marlrer which has thus become disabled and toimmediately seize eitherthe same or To accomplish these desirable ends,the

system is so arranged that if the marker encounters trouble after itsseizure and a given interval of time, normally sufiicient to permit thecomplete operation of the marker, expires, said marker will beimmediatelv discharged. After the discharge of the disabled marker, thesender immediately zes a marker, which may be either the same ornewunarker according to the busy and idle condition of all markersavailable. After the re-seizure of another marker, a new attempt is madeto operate the switch to extend the connection.

At the instant themarker is seized, the re lay 600 operates aspreviously explained. As soon thereafter as the constantly operatinginterrupter 637 completes its upper contact, the relay 601 operates asfollows:

battery, through the winding of relay 601,

normal contact of said relay, outer left con-- tact. of relay 600, toground at the upper contact of interrupter 637. Following the closure ofthe upuer contact of the interrupter. an interval of time expires beforethe closure of the lower contact which is sufficient to permit themarker, if acting normally, to complete the exercise of its function.If, however, the marker finds trouble and refusesto proceed, theinterrupter 63'? on final ly closing its lower contact causes theoperation of time measuring relay 602. The circuit may be traced frombattery, through the winding of said relay, right contact of re lay 601,to ground at the lower contact of interrupter 637. Relay 602 closes anobvious circuit for the lamp 638, which illuminates to notify theattendant that the mall;-

er is in trouble. The relay 602, which is slow to release, ten'iporarilylocks in a circuit from battery, through its winding and inner rightcontact, normal contact of key 639, to ground at the outer right contactof relay 600. Relay 602 at its inner left back contact opens the lockingci cuit of the relay 600. Relay 600, however, still remains energizedunder control of the sender. Relay 602 furthermore, causes the operationof relay 811 in the sender by means of a circuit from battery, throughthe winding of said relay, conductor 325, connector 400, conductor 4:22,out-er right contact of relay .602,

with the first idle marlzer.

to ground at the outer right contact of relay 60d Slow-release relay 311operates and severs the operating circuit oi relay 600. Relay 00thereupon releases and brings about the release of the marker from thesender 1n the manner hereinbeiore described. Relay (500 also opens thecircuit of relay 602. All relays in the marker which have 1 eenoperated, are released. Also the frame connector and trunk connectors800 and 801 are restored to normal, provided their operation has beeneither started or completed. I

Since the key 639 is in its normal position as shown in the drawing, themarker will immediately 'e restored to common use and may again beseized either by the sender shown or by other senders, as though notrouble had happened.

As soon following the di.:cha: marrer the slow relay 31.circuithereinbelore traced pleted tor relay 600. a vice e00 is actuatedto re- The first idic n'ia'rlrer may hang en to be the same one whichwas previously used or it may be any ot the otherniarkersi lhillowingthassociation of the sender with the marl d, the i.-

reeistcrs 109 is transferred to t marker registers. the translator isoperated, and the ophrat-ions hereinbctore described proceed in a secondattempt to control the CllStlJJt s elector switch 200 to extend thetrunk 102. it no trouble is encountered by the marker this time, theconnection proceeds and the switch 200 is successfully operated.r-lowcver, it trouble is again encountered for one reason or another andthe time measuring device in the marker counts a predetermined intervathen the marker is discharged and another attempt is made.

This procedure will continue until the sender has succeeded inassociating itselt with a'marlzer which is capable of fully completingits functions.

It the attendant notes that any particular marlzer is show' signs oftrouble frequent- 1y, he i'nay throw he key 639 to its actuatedposition. The result ot throwing the key (339 is to so modify thecircuits of the marker that when the inarl cr is subsequently dischargedon account oi? trouble condition, it will be indefinitely held out ofservice and cannot be select d by a sender. "Recalling the point in theoperation where the relay 602 actuates at the end the time interval, itwill be noted that this relay now locks permanently to ground throughthe key 639.

Relay ($02 in its operated condition, closes a holding circuit for therelay e08 associated with the connector This latter circuit may betraced from battery, through the right winding of relay 4108, conductor424, to ground at the outer leit contact of relay 602. The relay 408renders the marker non-selectable by extending the start wire through tothe next relay beyond corresponding to the next marker in order.

After the marker has been investigated and the cause of the troubleremedied, it may be restored to service oy rel asing the key 639.

hat is claimed is:

1. In a telephone system, a selective switch. means for extending aconnection to said switch, a controlling mechanism, means for seizingsaid mechanism for use, said mechanism arranged to progress through asequence of operations for governing the se ective operation of saidswitch to further e: .end said connection, means for rcleasing saidmechanism it it fails to tuction nor1nal ly without releasing saidconnection, and

means tor causing the reseizure of said mechanism in a repeated attemptto go'vern the operation of said switch.

' ln telephone system, a selective switch, means for extending talkingconnection to said switch, a controlling mechanism, means for seizingsaid mechanism, leans for connecting said mechanism to the switch. saidmechanism arranged to progress t 1 a sequence ot operations for controlln the selective operation of said switch t .urt icr extend theconnection, means fordi.connecting said mechanism from the switch andfor rendering the mechanism available for reseizure it it fails tofunction normally without releasing said connection, and means forcausing the reseizure of said niechanisn'i immediately in a secondattempt to control the operation of said switch.

3. in a telephone system, a selective switch, means for extending aconnection to said switch, a register senoer. a controlling mechanism,means for connecting said sender to said mechanism, means in saic senderfor variably setting said mechanism, said mechanism arranged to controlhe se lective operation of said switch to further extend saidconnection. means for releasing said mechanism from the sender when suchmechanism fails to function normally with out disturbing the e endedconnection, and means for causing s d sender to reseize said mechanismin a further attenpt to control the selective operation of said switch.

d. In a telephone system, a selective switch, means for ez'itending aconnec'ion to said switch, a marker for controlling the selectiveoperation of said switch, means for seizing said ma her for use, a timemeasur ing device for releasing said marker it it fails to functionproperly after its seizure without disturbing th extended connection,and means for causing the reseizure of said marker in a turther attemptto control the operation of said switch to further extend saidconnection.

5. In a telephone system, an automatic,

I suflicientto allowthe marker, if functioning normally, to control saidswitch, means effective at the end of the interval when the markerencounters trouble for releasing said marker without disturbing theextended connection, and means for causing the reseizure of said markerin a further atv tempt to control the operation of said switch.

6. In a telephone system a selective switch, means for extending aconnection thereto, a plurality of markers each arranged to selectivelycontrol the operation of said switch, means for seizing one of saidmarkers for use, 'means for releasing the seized marker if it fails tofunction normally without releasing the extended connec tion, and meansfor thereupon causing the seizureof anyone of said markers'in a furtherattempt to control the operation of said switch.

7. In a. telephone system, a selective switch, means for extending aconnection to said switch,;a plurality of markers each arranged toselectively operate said switch to further extend said connection, meansfor seizing an idle one of said markers for use, in a time measuringdevice for releasing the the selective operation of said switch tofurther extend the connection, means for connecting one of said sendersto an idle one of said markers, means controlled by the sender forsetting the marker, means for releasingthe connected marker if it failsto progress normally in its operation, and means for thereuponconnecting the sender to anyone of said markers, depending upon the busyor idle condition of such marker, in a repeated attempt to control theoperation of said switch.

9. In a telephone system, a selective switch, a plurality of markerseacharranged to selectively operate said switch, means for seizing thefirst idle marker for use, means for releasing the seized marker if itfails to function normally, means for rendering the released markernon-selectable,fand means for thereuponseizing an idle one of thereoperate said switch.

10. In a telephone system, a selective switch, .a plurality of markerseach arranged to selectively control the operation ,ofsaid switch, meansfor seizing an idle one of said markers for use, means for releasing theseized marker if it fails to progress normally with its functions, meansfor thereupon seizing one of said markers in a repeated attempt tocontrol the operation of said switch, and .manual means for determiningwhether a marker which has been maining markers in a repeated attempt toreleased on account of trouble shall be withmeans for taking 'saidmechanism into use,

said mechanism arranged/to govern the se lective operation of saidswitch to further extend said connection, means for releasing saidmechanism without releasing said connection, and means for again takingsaid mechanism into use in'a repeated attempt to govern the operation ofsaid switch.

.12. In a telephone system, a selective switch, means for extending aconnection to said switch,a plurality of controlling mechanisms eacharranged to selectively operate said switch, means for seizing an idleone of saidmechanism for'use, means for releasing the seized mechanismwithout releasing said connection, and means'for again seizing one ofsaid mechanisms in a repeated attempt to selectively operatesaid switch.

In witness whereof, I hereuntosubscribe SAMUEL B. WILLIAMS.

